The invention pertains to a method for producing a barrel marking on the inner side of the barrel of a firearm, as well as to thusly marked barrels. Barrel markings on firearms are used for marking projectiles fired from the respective firearm and to thusly allow a largely definite allocation of a projectile to the weapon from which it was fired. Various methods for producing such markings are known. The invention also pertains to barrels manufactured in accordance with this method, as well as to a device for carrying out this method.
A method in which the markings are produced by means of a finger-like tool that is inserted into the barrel and the movements of which follow the rifling of the barrel is known from US 2001/0029690 A1, the disclosure of which is incorporated into the present application by reference. In this case, a thin photoresist film is applied onto the inner wall of the barrel, with the marking subsequently being produced at the intended locations by means of an exposure process. Leaving aside the numerous production steps and the drying times to be observed in between these steps, etc., each individual step of this method is complicated, e.g., the strip-shaped exposure in the interior of the barrel.
A method for producing a barrel marking is also known from AT 402 702 B by the applicant. In this case, a statistical pattern that correspondingly marks the projectile is produced in the muzzle region of the barrel by means of spark erosion. The disclosure of this publication is incorporated into the present application by reference.
A different barrel marking in the form of marking grooves is known from U.S. Pat. No. 4,175,346 A, the disclosure of which is incorporated into the present application by reference. The barrel marking is only described in a very abstract form in this publication, with the main focus pertaining to the combination of different widths and different arrangements of the marking grooves in the barrel. It is only described very summarily how this complex marking can be produced. Possible methods mentioned in this publication are:
1. Cold forming over a core;
2. Embossing or punching, wherein not even a brief explanation of this method is provided;
3. Electrolytic material removal by covering certain regions of the inner wall of the barrel and carrying out a subsequent anodic erosion of the uncovered surfaces; and
4. Firing a projectile that carries corresponding projections and thusly produces the markings while it passes through the barrel.
None of the above-mentioned methods is suitable for practical applications because either the dimensional accuracy of the barrel is negatively influenced (in the two first-mentioned methods) or the costs (for carrying out the two latter-mentioned methods) are enormous.
The publications listed below are not quite as closely related to the invention as the aforementioned state of the art: DE 30 45 443 C; DE 37 28 622 C; U.S. Pat. No. 3,777,385 A; U.S. Pat. No. 4,035,942 A; U.S. Pat. No. 4,690,737 A; U.S. Pat. No. 4,936,608 A; U.S. Pat. No. 5,004,529 A and EP 0 438 870 A. These publications pertain to etching processes, electrochemical machining processes, barrels consisting of several sections, the production of markings by means of lasers, the utilization of one or more marking rings in the barrel, the general utilization of lasers and spark erosion methods for producing the markings, etc. None of the disclosed solutions allows an economical production of barrel markings which is also technically feasible. The disclosure of all these publications is incorporated into the present application by reference.
Based on the aforementioned state of the art, the invention aims to disclose a method that makes it possible to easily produce barrel markings, namely not only stochastic markings as proposed in AT 402 702 B, but also markings that correspond to a code or a scheme as disclosed in U.S. Pat. No. 4,175,346 A or US 2001/0029690 A1, and thus, if desired, to make it possible to realize a simple and definitive allocation of a projectile to a barrel or a group of barrels.
The invention proposes that at least one groove which follows the rifling of the barrel be produced in the barrel wall during the manufacture of the barrel by means of a finger-like tool that can be displaced relative to the longitudinal axis of the barrel and turned about the longitudinal axis of the barrel.
In this case, the tool mechanically produces the groove in the inner wall of the barrel material, for example, by means of a diamond tip, a hard metal tip or the like, or by means of a hard metal wheel or the like.
In the description and in the claims, the term xe2x80x9cfollowing the rifling of the barrelxe2x80x9d refers to the fact that the marking in rifled firearms has the same axial pitch as said rifling. In smooth barrels, the marking extends linearly along a generatrix, i.e., the marking practically follows a zero-rifling.
The method according to the invention is equally suitable for weapons with a smooth barrel and weapons with individual riflings. In addition, the invention may also be utilized in so-called barrels with hexagonal cross section or another barrel design.
Before the invention is described below with reference to the figures, one typical method for manufacturing the barrel of a pistol is briefly discussed. Naturally, the method according to the invention may also be used for the barrels of all other types of firearms as long as they contain a barrel, as well as for all types of barrels, e.g., smooth barrels, rifled barrels, etc. The cores are usually drilled out of cylindrical blanks, with the final dimensions of the inner barrel wall subsequently being realized by means of cold forging, drawing or electrolytic methods, and with, if applicable, the riflings or a polygonal shape subsequently being produced. The corresponding outside shape is then realized at the location of the subsequent breech by means of mechanical processing, wherein a correlation between the position of the riflings and the circumferential orientation usually no longer exists due to the required change of processing machines.
According to the invention, a simple tool of finger-shaped design is inserted into the barrel by at least a short section from the muzzle side after the inner barrel surface is manufactured and before material is removed from the outside of the workpiece, wherein the corresponding groove on the inner barrel wall is produced while said tool is inserted into or pulled out of the barrel. Since the processing machine for producing rifled barrels requires a device for simultaneously turning and axially displacing a tool, it is very simple to always move the finger-like tool along a path that correspond to the rifling. Any type of code can be produced on the inner walls of the barrel by correspondingly arranging the grooves within predetermined circumferential distances. This is realized by correspondingly turning the barrel or the tool between the production of two grooves. Codes of this type are sufficiently known from the aforementioned state of the art and consequently not explained in detail.
The code does not have to extend over the entire length of the barrel. It is advantageous to realize the code in the muzzle region so as to prevent the marking of the projectile from becoming weakened or even rendered unrecognizable by an ensuing unmarked barrel section.